Compression formats and codecs for audio and video.

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From mp3 format to H.265 and VP9 codecs, these are the most widely used audio and video compression formats.

The videos we watch on YouTube, the music we listen to through Spotify and iTunes, the photos taken with the digital camera. The multimedia content that we process daily is the result of a compression process that allows you to enjoy them without major headaches. Due to the weight of the files, the need arose to reduce their size so that they take up less disk space and can be exchanged faster on the network.

Over the years, two different compression techniques have been developed: one involving loss of information and one involving loss of information. This has led to the emergence of various codecs and formats, such as MPEG, MP3, MPEG-H and many others.

Without loss and without loss

Media compression can occur in two ways: lossy (translated with “lossless”) and lossless (translated with “lossless”). In the first case, encoding audio and video files involves loss of some information that is considered “useless” or non-essential. The files obtained through this process will have a lower quality than the original files, but the human eye or ear should not notice major differences. In an mp3 file, for example, the ultrasound is removed; In the case of a Jpeg file, groups of adjacent pixels and the like can be chromatically grouped into larger blocks and lose a certain amount of detail depending on the amount of compression performed.

Comparison of MPEG formats

Losses without compression ensure that no loss of information is lost in the coding process. This is possible by using certain algorithms that eliminate redundant information by replacing it with some sort of “placeholder”. For example, the LLE (Run Length Encoding) algorithm identifies the usual repetition in the bitstream files and replaces them with a single symbol and the number of repetitions.

Video compression formats

DivX, Xvid. They belong to one of the first generations of the era of online multimedia content. In essence, these are two “twin” codecs: DivX was born as the proprietary format of the homonymous software house; XviD as a free and open source alternative with similar, if not identical, functionalities. They achieved great success and widespread popularity thanks to their ability to compress long clips (even full-length movies) into small files while maintaining a good quality level.

Comparing formats to the Internet.

– Google code. Google is increasingly engaged in the multimedia sector and is increasingly committed to investing in technologies that can minimize the impact on users’ bandwidth consumption. An example of this is the set of codecs and video compression formats developed in recent years. The latest addition is the VP9 codec, which is compliant with the 4K standard and is capable of guaranteeing a high reproduction quality associated with small files.

–H.264. Among the most widely used video compression formats to create and distribute movies and videos of all sizes and resolutions, the H.264 codec (also known as MPEG-4 Part 10 AVC) is also known to be one of the Blue Disks-ray encoding standards . It is capable of guaranteeing excellent video quality at low bitrate levels (ie smaller files) and is widely used by web video streaming services (Vimeo, iTunes) and video playback software (Adobe Flashplayer and Microsoft Silverlight)

–H.265. The inheritance of the H.264 codec (officially released only in April 2013) theoretically guarantees a double compression compared to its predecessor: therefore, for the same video quality, a video file compressed with the H.265 codec will weigh approximately half of that movie compressed with the H.264 codec. It is compatible with the 8K standard, which guarantees viewing videos with a resolution up to 8,192×4,320 pixels

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What is a codec exactly

Has it happened to you that you download a video file and then you cannot use it in your player? Or that you finally finish editing your video clip and it takes years to upload to the Internet? You might think it is a problem with your file. You are not wrong, only the question is more specific: it is about the codec and container you are using.

Maybe they are somewhat strange terms, but they are gaining more and more popularity due to the growing community in online video and audiovisual production. So if you plan to start your career as a youtuber, take into account the information, because if you end up with a final video with a weight of 1 GB it will not be fun waiting for it to go up …

What is a codec?

Those who do video editing know full well that storage space can be a problem. It is better to have the material you record in its original format, but most of the time this involves a considerable amount of GB of space. For example, if you record an hour of content with an HD camera, you may need … up to 410 GB! This is difficult to keep it, much more if you want to transmit it to other media. This is where the topic gets interesting.

The term codec refers to the video or audio compression and decompression process. It is a tool that encodes video using algorithms and converts it into information. This way you can decrease the file size.

The choice of the codec depends on different factors. You must mainly take into account the means of reproduction for the final product. However, encoding is not enough for its reproduction, it is also required to “pack” the information in order to present it. We are talking about containers.

What are those containers?

Suppose you just finished editing a video. The final file contains both images and audio, so you require a way to display it just as you prepared it. This “package” is basically what many refer to when they talk about the format of a file. So a container can accept different codecs, while players can use certain containers. For example, the VLC player accepts almost all containers.

Lossy and lossless codecs (lossy and lossless)

There are different types of compression, as we will see later. However, all of them can be divided into two categories: with or without loss. Loss of what? Quality. For example, in the case of audio files, it is not the same to listen to a song in FLAC (Free Lossless Audio Codec) format to one in MP3 (MPEG Audio Layer III). The first is coded in such a way that almost no information is lost when compressing, that is, fidelity is maintained.

The same goes for the video. Wanting to save storage space, lossy files, ie lossy, are compressed. This makes them much easier to manage. However, it is unavoidable to deal with data loss and therefore image or audio fidelity. On the other hand, when you want to maintain the highest possible quality and have no space problem, lossless or lossless compressors are used. Again, it all depends on the purpose of your file. Will it be a web video? A projection? Film contest?

Video codecs

Below you will find a list of the most popular codecs. We will not go too far into others, since an average consumer rarely requires those who are specialized.

DV and HDV

Do you remember the tapes or cassettes to record video? This type of capture uses the DV codec, the standard defined by various electronic sales companies. Over time, HDV emerged, as they had to adjust to the demand for high-definition video.

H.264 / MPEG-4 AVC

Platforms like YouTube have made the popularity of this codec grow quite a bit, as it is their recommendation to upload your videos. It is one of the most suggested thanks to the fact that it considerably reduces the file size without sacrificing much image fidelity. Multiple cameras use the codec, as do web video and Blu-ray.

Microsoft VC-1

Microsoft has its encoding mode for Blu-ray content. It also works in your Microsoft Silverlight tool.

MJPEG (Motion JPEG)

Many video cameras used to capture material with this codec. Its name comes from the group that created it, the Joint Picture Experts Group. If the name seems familiar to you, it is because they are the same ones that created the JPEG still image compression codec.

MPEG-1

Before H.264 there was MPEG-1. This used to be the standard for online video, although the emergence of new formats has left it behind.

MPEG-2

This format is merely for compressing information to DVD video.

WMV (Windows Media Video)

This is another codec that has practically disappeared. It focuses on the Microsoft family.

Audio codecs

As we mentioned before, codecs can be used with or without data loss. As for audio, there is a huge difference not only in quality (especially with good headphones), but also in the file size. Do you prefer an entire album in MP3 or a few songs in FLAC?

ACC (Advanced Audio Coding)

YouTube, Android, iOS, iTunes and more have adopted this compression method as their standard. AAC was devised as the next step for MP3, although it still has a long way to go. However, AAC tends to be of better quality. It is a lossy codec.

FLAC (Free Lossless Audio Codec)

Recommended for true audiophiles. Its development is open source and is considered a great alternative to MP3 or CD if you want to get the best possible quality. It is also recommended because it can compress a file by up to 60% without loss of information.

MP3 (MPEG-1 Audio Layer 3)

It is currently the best known format for audio. It is not of the best quality, but its compression quality is what has made it so successful. It ignores the information that corresponds to the sounds that we do not hear in our hearing range, thus eliminating “irrelevant” space. It can be reduced between 75 and 95% of the original size.

Windows Media Audio (WMA)

This is another of Microsoft’s products. It never really took off, the MP3 format took care of it. It has two versions, one with and without loss of information, although the same extension (WMA) is used for both.

Containers

You have finished editing your video. You have already chosen the codec and now you must choose the means by which you can transport and reproduce the information you have assembled. We leave you the best known. Define which one is indicated according to the purpose of your product.

ASF (Advanced Systems Format)

This is a format that belongs to the Microsoft family. Its supported file types include .asf, .wma, and .wmv. The container works well if your devices are Microsoft, but it is not well received by other systems, not to mention the loss of popularity with other containers.

AVI (Audio Video Interleave)

We have all come across this one in one or the other download. It is still in multiple instances, but don’t consider it your first (or second) option if you’re creating content.

AVCHD

This format works with the content captured with video cameras.

Flash

Adobe has its own container, which was originally created by Macromedia. Many have made it clear that it is a limited container. For example, Mozilla Firefox no longer supports such files.

MKV (Matroska Multimedia Container)

This format increasingly gains more ground thanks to its versatility. It accepts almost any audio and video codec. It also has the ability to have multiple video, audio and text channels. It is open source, so it has a generous community.

MP4

It is one of the most popular containers. It works with the H.264 codec, making it ideal for working with online audiovisual content. As for audio, it usually uses AAC or AC3 codecs. It was created by the Motion Pictures Expert Group.

MPEG and BDAV MPEG-2

Both are used for discs, the first for DVD and the second for Blu-ray. Generally the file extensions with this codec are TS, VOB, MPG and SVCD.

Quicktime

Now we see the turn of the Apple family. Part of its appeal is the separation of information into different channels (video, audio and text). It also allows for better editing of the metadata. It compares a lot with the MP4 container.

All about installing audio and video codecs

Nowadays, with the massification of computer tools and the expansion of the Internet, almost all computer users use their equipment not only for simple office tasks, but also for fun and personal enjoyment, so multimedia tasks are They have become a more than common activity on any home PC.

While most users know that to play a video, listen to a song and view an image, it is not enough to play the file, but also the system must have the necessary codecs for it, the truth is that a large percentage of Users are completely unaware of what codecs are and what they are used for.

It should be noted that the term codec comes from an abbreviation of the set of words encoder and decoder, and as the name implies, they consist of a software specification that allows compressing and decompressing files.

What are codecs? What are codecs for?

In general, the different existing codecs are currently used to compress video, audio and image files, in order to make them smaller than their original source, to allow them to be easier to handle and Work on a computer.

Therefore, when trying to play for example a video file in an AVI container, which has been encoded with the Xvid codec, it will be necessary to have the same codec on the computer, since otherwise the reproduction will be impossible.

It is worth mentioning that codecs are also commonly used to compress data streams and signals, that is, to stream Internet radio and television, or allow a quality videoconference.

Most of the multimedia files contain video, audio and references data for the synchronization of both, so it must be necessary to apply the appropriate codecs to play a movie on our PC.

Compression of audio and video files

When using codecs to compress a multimedia file, in general a result will be obtained with some loss of quality, since in order to reduce the size of the original source, a loss of information will occur during the process.

However, there are also some types of codecs that do not report losses, such as FLAC and MSU, that allow the reproduction of a lossless audio or video file when the file is re-encoded.

However, in general codecs that compress with some loss of information are used, since the fundamental function of the use of codecs is to significantly reduce the size of the files to facilitate their manipulation.

Usually, when a video file is transformed with codecs, an automatic process is carried out that causes the codec to cut some of the information regarding the original image or sound, and then readjust it to a smaller space, and Finally codify it.

Most used audio and video codecs

In order to reproduce a file that has been compressed with some codec, it is essential that our system has the necessary codecs for decompression, for which codec packages can be installed, which generally contain the most used types of codecs. The most recommended codec packages are the ELISOFT Codec Pack and the K-Lite Codec Pack.

Although there are many codecs to reduce the size of multimedia files, the truth is that at present some are usually the most popular, as is the case of mp3 for audio and mp4 for video.

Next we tell you which ones with the audio and video codecs most used by users.

Most used audio codecs

Currently, audio codecs have been widely disseminated, as they are used by users to compress for example full music albums, so that they take up less space.

Keep in mind that a common audio disc can occupy up to 700 Mb, that is, a complete CD, while albums transformed to MP3 give rise to a huge storage capacity, allowing you to save between 7 and 8 discs on a single CD , because an MP3 compressed disk usually occupies between 80 and 90 Mb. depending on the bitrate rate at which they were worked.

At present, the most popular audio codecs are the MP3 format, the Ogg Vorbis, which is characterized by being a codec belonging to free software, and the AC3 that is usually used in DVD compressions as it is a multichannel codec (5.1).

Due to its great popularity obtained in recent years thanks to its massive dissemination on the Internet, especially in sites that allow the purchase and download of audio files, the leading audio compression format is undoubtedly the MP3.